Add a JNI to get the frequency

Bug: 4192129
Change-Id: I3f220f5a10114d4eb23956148076cf76220bda0f
diff --git a/native/jni/src/dictionary.cpp b/native/jni/src/dictionary.cpp
index 65d0f73..1fb0247 100644
--- a/native/jni/src/dictionary.cpp
+++ b/native/jni/src/dictionary.cpp
@@ -55,8 +55,8 @@
     delete mBigramDictionary;
 }
 
-bool Dictionary::isValidWord(const int32_t *word, int length) {
-    return mUnigramDictionary->isValidWord(word, length);
+int Dictionary::getFrequency(const int32_t *word, int length) {
+    return mUnigramDictionary->getFrequency(word, length);
 }
 
 bool Dictionary::isValidBigram(const int32_t *word1, int length1, const int32_t *word2,